Nowadays, with the development of the touch technology, more and more terminal devices, such as notebooks, have touch functions. For example, some notebooks have keyboards and touch screens, thereby allowing users to input with keyboards or by touching. However, the costs of the notebooks described above are high. Further, in some notebooks, a touch screens is also provided on the host portion (body) of the notebook and a virtual keyboard is displayed on the touch screen so as to enable the user to input with the soft keyboard by way of touch. However, since two display screens are provided in the above-described notebook, it is difficult to control the thickness of the notebook, and the two display screens are bound to increase the cost and power consumption of the notebook.